Again, I kind of agree - but this discussion has nothing to do with OP's technical ability or project management, it's his ability as a businessman that he's struggling with, and a lot of Kevin's content helps people overcome that mental hurdle.
This helped me tremendously in my early days: https://leanpub.com/freelancedeveloperbook. I was in the same situation: I knew enough about the day job (web design/dev), but I didn't know best business practices and how to price according to my true value.
The only other advice I have is to pick up experience in an agency - I've worked in a few over the years and you begin to see how they operate and secure business; whether they do it good or bad, it's all a learning experience.
This helped me tremendously in my early days: https://leanpub.com/freelancedeveloperbook. I was in the same situation: I knew enough about the day job (web design/dev), but I didn't know best business practices and how to price according to my true value.
The only other advice I have is to pick up experience in an agency - I've worked in a few over the years and you begin to see how they operate and secure business; whether they do it good or bad, it's all a learning experience.